Set just prior to the beginning of the Heresy, Legion follows the story of the manipulative Alpha Legion and their motivations for the role they will take in the coming civil war. After the diversion of Descent of Angels, Legion brings back an enjoyable story with solid action, entertaining characters, a few quirky moments, mystery, and all the elements of the 40K universe.
The Alpha Legion was the twentieth legion of the Imperium's Space Marines. Known for their mysterious and manipulative ways, Legion gives us an in depth view into this chapter of Marines and the reasoning for their actions in the Horus Heresy. The story opens up on the planet Nurth, where a division of the Imperial Army is locked in a battle with the native residents, the Nurthenes . Initially unknown to the Imperial Guard regiment, the Alpha Legion has been called in to help finish the fight and it doesn't take long for the first of the book's mysteries to appear. Unlike the previous novel in the Horus Heresy Series, Legion does an excellent job bringing closure to all of the mysterious in introduces throughout the book.
There are a number of main characters active throughout the story, but thanks to different sets unique qualities, each one adds a different flavor to the various events. Also due to the different military roles and objectives the characters are pursuing, several humorous encounters will occur between the groups of characters. Just as a total side note, my favorite character was the genetically engineered Thylacine that always tagged along with the Imperial Commander.
Since most of the book is set on the planet Nurth, there is plenty of action to be had. From small scale street pursuits to battles involving lines of Imperial Armor and Titans, this book has them all. It lacks the over the top comedic level of violence that appears in some 40K novels, but that absence gives the book a slightly increased sense of reality.
Personally, I would have liked to see a novel which advances the Horus Heresy storyline, but Legion is a fun and enjoyable read and belongs in the 40K universe. I read through it at my normal pace and didn't get distracted by anything else. I certainly have no way of knowing if future books will build on any of the characters or events from this story, but if you got some free time, give Legion a read.